The overarching goals of this research are to better understand the development of self-regulation in young children at risk for Autism Spectrum Disorders (ASD) and to elucidate the longitudinal associations between self-regulation and sleep in these children. It is critically important to study the infant siblings of children with ASD because they are at risk not only for ASD, but also for numerous negative developmental outcomes including difficulties in language, social-emotional functioning, attention, behavior and cognition. Previous studies of infant siblings at risk for ASD have focused mainly on the three core deficit areas of communication, social, and restricted/repetitive behavior, but recent research and preliminary data suggest that difficulties of this group extend more broadly to difficulties with self-regulation. Specifically, problems with attention, behavior and negative emotion control appear elevated in infant siblings of children with ASD. Difficulties in these areas are robustly associated with sleep. Children with sleep problems have more difficulties with attention and behavior control and exhibit more negative affect and emotional reactivity. Additional research on siblings of children with ASD is needed to elucidate their adverse developmental outcomes and the proposed studies aim to do this within the domains of self-regulation and sleep. Two studies are proposed to examine self-regulation and sleep problems and the dynamic developmental progression between them in two groups of children: infant siblings of children with ASD (high risk) and infant siblings of typically developing children (low risk). The first is a cross-sectional study examining the rates of self-regulation and sleep problems in high risk infant siblings at 24 and 36 months of age. The second is a prospective longitudinal study that assesses children at 18, 24, and 30 months of age to examine the developmental progression and associations between self-regulation and sleep. Within each study self-regulation and sleep will be assessed with behavioral, physiological, and parent-report measures. The ultimate significance of this line of research is to improve the developmental trajectories and family life of children at risk for ASD by drawing attention to often unconsidered areas of development: self-regulation and sleep. Understanding the rates of sleep problems and the roles of sleep in self-regulation has the potential to inform assessment, treatment and parenting guidelines. Dr. Schwichtenberg is an ideal candidate for the proposed studies with her educational and research experience in self-regulation and sleep development. She has specialized training in the physiological assessment of sleep and two behavioral self-regulation paradigms. Her knowledge of sleep and self- regulation includes assessment procedures, coding, screening, and analyzing and she has published in both areas. Dr. Schwichtenberg also has experience on two prospective longitudinal studies of children developing at risk, making her keenly aware of the real life considerations needed to complete such a study. With the training proposed in this application she will secure the final clinical, methodological, statistical, and lab management skills needed to transition from a postdoctoral scholar to an independent researcher with a unique line of research in the developmental processes of self-regulation and sleep in children developing at risk. Dr. Schwichtenberg's career goals are to obtain a tenure-track position in a department of Psychology or Human Development at a university with an established developmental disabilities center and to launch a research lab that studies a variety of self-regulatory capacities in young children with and at risk for developmental disabilities. Dr. Schwichtenberg's training plan will be carried out at one of the foremost centers for excellence in developmental disabilities, the University of California - Davis, M.I.N.D. Institute (Medical Investigation of Neurodevelopmental Disorders). Her training includes advancing her skills in clinical assessment, learning a specialized non-invasive sleep assessment technique (videosomnography), securing advanced statistical training in longitudinal data analysis, learning eye-tracking assessment and coding methods, and completing structured training in laboratory management and leadership. Her sponsors Dr. Sally Ozonoff and Dr. Thomas Anders are two internationally recognized scholars in the areas of autism and sleep and are dedicated to her training and future success.